The impact of insurance status on the therapy and outcome of STEMI patients in Switzerland

Abstract Background Current literature reports large disparities in treatments and outcomes in patients treated for acute myocardial infarction based on insurance status. However, it is unknown if this applies to ST-elevation myocardial infarction (STEMI) patients in Switzerland, where basic health insurance is mandatory and covers all essential treatments for all citizens, and supplementary private insurance (SPI) can be purchased optionally. Methods STEMI patients enrolled in the nationwide Acute Myocardial Infarction in Switzerland (AMIS) Plus registry between 2005 and 2023 were retrospectively analysed. Patients with basic insurance and those with SPI were compared using descriptive statistics. Then, temporal trends of full guideline-recommended treatment (FGRT), comprising optimal medical therapy (OMT) plus percutaneous coronary intervention, stratified by insurance type, were assessed via linear-by-linear association. Finally, multivariate logistic mixed effects models were fitted to assess whether a patient’s insurance type influenced treatment and outcomes. Results Among 16,463 patients included, 13,023 (79.1%) had basic insurance. Compared with patients who had SPI, patients with basic insurance only were younger (64 years vs. 69 years, p0.001) and more likely male (74.9% vs. 72.0%, p0.001). They also had higher rates of obesity (20.7% vs. 17.6%, p0.001) and diabetes (19.6% vs. 16.5%, p0.001), and were more often active smokers (43.1% vs. 30.7%, p0.001), but less likely to have cancer than patients with SPI (4.6% vs. 6.9%, p0.001). Unadjusted analyses showed that, compared to patients with SPI, patients with basic coverage more often received OMT (41.6% vs. 35.2%, p0.001) and FGRT (39.7% vs. 33.9%, p0.001, the Figure shows the corresponding temporal trends). In terms of in-hospital outcomes, patients with basic insurance had higher rates of crude in-hospital mortality (8.6% vs. 5.7%, p0.001) and major adverse cardiac and cerebrovascular events (MACCE) defined as in-hospital death, reinfarction or cerebrovascular event (9.7% vs. 6.9%, p0.001). After adjusting for confounders (age, sex, pre-hospital resuscitation, obesity, connective tissue disease, Killip classification 2, impaired left ventricular ejection fraction, diabetes, cancer, smoking, maximum in-hospital creatine kinase level, glycemia and hospital), multivariate mixed effects models revealed that insurance type (basic vs. SPI) was not significantly associated with OMT (adjusted odds ratio, 1.04; 95% confidence interval, 0.93-1.16; p=0.53) or FGRT (1.01; 0.90-1.13; p=0.88). Multivariate analysis also showed that in-hospital mortality (1.32; 0.94-1.87; p=0.11) and MACCE (1.32; 0.99-1.77; p=0.06) were similar in patients with basic insurance only and in those with SPI. Conclusion This study showed that in Switzerland, insurance type did not significantly impact treatment or in-hospital outcomes of STEMI patients, suggesting a high level of equity in acute cardiac care.